Short answer. Not on that ground alone. The Labor Code allows dismissal for failing to qualify as a regular employee only under reasonable standards the employer made known to you at the time you were engaged. If those standards were never communicated at hiring, dismissal for failing to meet them does not fit within what the article permits.
What the law says
The services of an employee who has been engaged on a probationary basis may be terminated for a just cause or when he fails to qualify as a regular employee in accordance with reasonable standards made known by the employer to the employee at the time of his engagement.
Labor Code, Article 281 — Probationary Employment. Read the full provision →
Two separate grounds, and this question is about one of them
Article 281 gives an employer two grounds for ending probationary employment: a just cause, or failure to qualify as a regular employee under reasonable standards. The two are independent of each other. This question concerns the second ground, and the article ties it to a specific condition — the standards have to be reasonable and made known by the employer to the employee at the time of his engagement. Both elements are written into the ground itself, not treated as optional refinements.
Why "made known at the time of engagement" is not a minor detail
The timing the article specifies is exact: at the time of his engagement, meaning when you were hired, not partway through probation and not after the fact when performance is already being questioned. Standards disclosed only in hindsight, once an employer has decided the working relationship is not working out, are not what the article describes. The article conditions this entire ground for termination on the standards having been communicated at the outset.
What follows if the standards were never communicated
If no standards were made known to you when you were engaged, a dismissal grounded on "failing to qualify" against standards you were never told about does not fit the ground Article 281 describes for that kind of termination. That does not erase the separate just-cause ground, which stands on its own and does not require standards to have been disclosed in advance. But failure-to-qualify specifically, on this article's own terms, depends on those standards existing and having been communicated at hiring.
What to keep track of
Because this ground turns on whether standards were actually communicated and when, what matters is documentation from the time you were hired — your employment contract, any orientation materials, or written performance criteria given at the start. The absence of any such document, or evidence that criteria were introduced only later, is directly relevant to whether the standards were made known at the time Article 281 requires.